Boiler.



EDWARD B. PARKHURST, OF' WOBUBN, MASSACHUSETTS.

BOILB.

Specification of Letters'Patent.

Patented Aug. 1, 1905.

Application filed June 7, 1904. Serial No. 211,486.

.To (LZZ whom t may concer-7L:

Be it known that I, EDWARD B. PARKHURST,

Va citizen of the United States, residing at Woburn, in the county of Middlesex, State of Massachusetts, have invented a certain new and useful Improvement in Boilers and Furnaces Therefor, of which the following is a specification, reference being had therein to the accompanying drawings.

My invention relates to an improvement in boilers and furnaces therefor, and is adapted to increase the eiliciency of the boiler in the formation of steam without increasing the consumption of fuel and also to lessen the eX- pense of the'construction of the boiler. It is an improvement over the boiler shown in my Patent No. 576,686, issued February 9,1897, in the arrangement of certain parts at the rear of the furnace.

The invention will be fully understood from the following description, taken in connection with the accompanying drawings, and the novel features thereof will be particularly pointed out in the claims at the close of this specification.

boiler-tubes at 6. A smoke-uptake, with which the tubes 6 communicate, is designated 7 rThe boiler is also provided at 8 with a connection for the attachment of a steam-delivery pipefnot necessary to be shown) and at 9 with a hand-hole. All these parts are of the ordinary well-known construction, as shown in my Patent No. 57 6,686, and may be modified to suit particular circumstances without interfering with my invention. I have shown my invention in thisconnection because it is in this form that I have put the invention into actual practice; but it is evidentthat it may be applied to other forms'of boilers without departing from the spirit of the invention. The grate upon which the fire rests consists of a lower series of water-grate bars10 and an upper series 11, the two being connected at the front of the boiler by a water-box 101 and being slightly inclined upwardly toward the back of tlie furnace. The draft of the furnace is downward through the grate-bars of the upper grate 11 and upward through those of the lower series 10,thence passing to the combustion-chamber 80 and the boilertubes 6. The rear ends of the water-grate tubes 10 and 11 are connected by vertical pipes 102 and 111 with the crown-sheets of the boiler. The water-box 101 is connected with the lower part of the main portion of the boiler by three or more large water-tubes 12.y By'this means the circulation of water from the lower and cooler parts ofthe boiler A throughthe tubes 12, the grate-bars 10 and 1 1, and the vertical tubes 102 and 111 to the space above the crown sheets is obtained. This arrangement of grate-bars also is as described' in my patent previously referred to. Heretofore in the construction of this type of 1 boiler it has been my .practice to make the crown-sheets of the furnace arching and to place a partition of fire-clay, brick, or other suitable material in front of the vertical pipes 102 andlll connecting the water-grates with the boiler-space above the crown-sheets. I

vhave also been accustomed to provide a suitable arched casting, into which the vertical pipes enter; but I have found that such a construction is expensive and requires frequent renewal. In accordance with my present invention I make the front crown-sheets 15 of the boiler arched, as is usual, and the back sheets 16 flat and connect the two by a depending water-leg 14:, which serves as a partition between the lire-box and the combustion-chamber. By this means the evaporating-surface at the hottest part of the boiler is considerably increased and a fiat surface into which the vertical tubes 102 and 111 from the grate-bars 10 and 11 may enter is provided, thus doing away with the necessity of any casting. This construction also lessens the diiiiculty of obtaining tight joints between the crown-sheets and the tubes and does away with all danger of'leakage. The front crownsheets 15 are stayed in the usual manner, as shown at 151. Above the rear crown-sheets 16 I place crown-bars 161, provided at each end with legs 162 and 168, which support the crown-bars upon the end sheets 164 of the furnace and the Water-leg 14, respectively, in the usual manner. The usual stay-bolts 165 serve to support the crown-sheet from the crownbars. A suiiicien't number of these crownbars 161 is provided to carry the pressure upon the fiat crown-sheets 16. VBy placing the crown-bars 161 lengthwise of the boiler they do not interfere with the circulationin the boiler. Y

The water-leg or partition 14is formed from l for the said grate entering the said fiat crowna sheet or sheets of metal, as indicated in Fig. 2, and is carried backward, as shown at 141, a considerable distance, lthus reinforcing the crown-sheets about the points where the ends of the vertical tubes 102 and 111 enter. In order that the partition 14 may not be forced out of shape by pressure upon its interior, I provide stay-bolts 142 at convenient intervals throughout its length.

My invention provides aconstruction which may be manufactured at a minimum of eX- pense. It affords an increased evaporatingsurface over my previous construction and provides a partition which is but little affected by the intense heat of the furnace.

I claim as my invention- 1. In a furnace for boilers, the combination of an arched crown-sheet and a fiat crownsheet, a depending water-leg at the rear of the fire-box, and a water-grate connected at the rear end with the space above the flat crown- A sheet.

2. In a furnace for boilers, the combination of an arched crown-sheet, a flat crown-sheet, a depending Water-leg between the said crownsheets, a Water-tube grate, and connections sheet.

3. In a furnace for boilers, the combination of an arched crown-sheet, a fiat crown-sheet, a depending water-leg between the said crownsheets.,- an upper and a lower water-grate, connections for the water-grates entering the said flat crown-sheet and supply connections between the cooler part of the boiler and the water-grates.

4. In a furnace for boilers, the combination of an arched crown-sheet and a iiat crownsheet, a water-grate connected at the rear end with the space above the fiat crown-sheet, and a depending water-leg between the said arched and flat crown-sheets, said water-leg being composed of a sheet extending rearwardly and reinforcing the said flat crown-sheet at the point where the said water-grate is connected with the space above the said flat crown-sheet.

In testimony whereof I aiiix my signature in presence of two witnesses.

EDWARD B. PARKHURST.

Witnesses:

GEORGE P. DIKE, A. H. MORRISON. 

